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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Adsorption / desorption

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Administrative data

Link to relevant study record(s)

Description of key information

Adsorption to solid soil phase is not expected.

Key value for chemical safety assessment

Additional information

In accordance with column 2 of REACH Annexes VIII and IX, the study does not need to be conducted if based on the physicochemical properties the substance can be expected to have a low potential for adsorption (e.g. the substance has a low octanol water partition coefficient), or the substance and its relevant degradation products decompose rapidly. 1,4 -Dimethyl-1H-pyrazole (CAS 1072 -68 -0) has a low log Kow of 0.95 (at 25 °C at pH 6.1; Kurume, Report no. 80546, 1994). However, the substance is not readily biodegradable according to OECD criteria (see IUCLID Ch. 5.2.1).


In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

For the assessment of1,4-Dimethyl-1H-pyrazole(Q)SAR results were used for the estimation of the adsorption potential. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

Therefore, further experimental studies on the adsorption potential are not provided.

Although a study could be waived, the Koc was estimated using both models of KOCWIN v2.00 of EPI Suite v4.11. Using the Molecular Connectivity Index (MCI) which is regarded as more reliable compared to the log Kow method, the log Koc for the uncharged molecule was estimated to be 1.72. Based on the measured log Pow of 0.95 (see Ch. 4.7), the log Koc was estimated at 1.85 using the log Kow method. Both estimates refer to the uncharged molecule (BASF SE, 2016). At environmentally relevant conditions, the substance is present in its uncharged form (pKa = 2.77; SPARC, 2015). While the substance was completely inside the applicability domain of the MCI model, the substance was not within the applicability domain of the KOW method. Therefore, the estimate of the log Kow method may be less accurate.